Steel slag is an inevitable byproduct of steelmaking process, and is approximately 10% to 15% of the steel yield, therefore, the rapid and effective processing for steel slag, especially for high-temperature steel slag, directly influences the common run of steelmaking process and the sustainable development of steel companies. Due to the differences among various steel companies' steelmaking processes, the compositions and temperatures of steel slag produced during smelting are not completely identical: some high-temperature steel slag has an excellent fluidity, so that it can be poured out like water; some high-temperature steel slag has a poor fluidity, so that it cannot be easily poured out from a slag ladle (a container for containing and transporting high-temperature steel slag, also called as a slag basin), can only be poured out from the slag ladle by means of mechanical external force or slag ladle inversion.
In order to increase the service life of the slag ladle, and avoid a scouring to the bottom of the slag ladle when pouring in high-temperature steel slag, some steel companies lay some cold slag on the bottom of an empty slag ladle. When high-temperature steel slag is poured in, the portion of cold slag fuses together with the contacted high-temperature steel slag, and forms a large slag shell along with steel slag at the inner wall of the slag ladle. The slag shell is several tons heavy, and is approximately one third of total slag. This portion of slag is either held in the slag ladle, or poured out in a whole from the slag ladle, so that a suitable mechanical crushing is necessary for a subsequent processing, and dust emission is very serious.
Typically, the current processing methods for hot steel slag is a process of hot pouring, wind quenching, shallow tray, hot stuffing, or rolling cylinder, etc.
The process of hot pouring is a relatively original processing method, wherein high-temperature steel slag is poured out onto a designated place, heat of the steel slag dissipates by means of air cooling or slight water spraying, and it is necessary to continuously turn over the steel slag by an excavator or forklift in order to expedite cooling for increasing the processing efficiency; the steel slag after hot pouring cannot be directly utilized, it is necessary for the using by a user to stack and age it for several months, then crush and sort it. The whole processing procedure has a long flow, a large floor area, an execrable operating environment, a serious pollution, and tends to be substituted by other methods.
The process of wind quenching, such as those disclosed in JP24238276 and CN88211276, successfully achieves a rapid granulation processing to liquid steel slag, so that the slag granule after wind quenching is fine and uniform, has a stable performance, and can be utilized directly. Its shortcoming is that the processing subject of this method is limited strictly, i.e., only steel slag having an excellent fluidity can be processed, and steel slag having a higher viscosity and a poor fluidity cannot be processed.
Shallow tray type steel slag processing method increases the producing efficiency on the basis of hot pouring method, but still has shortcomings such as long period, large pollution, high operating fee, aging requirement.
Hot stuffing method for hot steel slag, such as those disclosed in CN02157162.7 and CN200410096981.0, achieves a rapid pulverization processing to steel slag, wherein during about 12 hours, steel slag having a temperature of about 800° C. is pulverized into fine powders in millimeter order by means of its thermal stress and chemical stress, is then sorted for acting as cement clinker directly. The method is relatively simple, can achieve a massive processing for steel slag; however, its shortcomings are also very obvious: in view of safety, this method can only process blocky steel slag having a temperature lower than 800° C., so that hotter steel slag should firstly be cooled outside of the hot stuffing pool, during which, it is necessary to turn over the steel slag repeatedly in order to increase the producing efficiency, causing a serious dust emission and thermal pollution.
Rolling cylinder type steel slag processing method, such as those disclosed in CN99127012.6 and CN200410054165.3, achieves at the first time for the concept of rapid processing high-temperature steel slag within a sealed container, so that high-temperature liquid slag having a temperature of about 1500° C. can be cooled dynamically, continuously and rapidly, and be crushed into granular slag having a temperature lower than 100° C. to be directly used by user, by means of the revolving sealed container. A massive dust-laden steam produced during processing is collectively discharged by a chimney after a purification processing, so that it eliminates the shortcomings, such as diffused steam, raised dust, in a conventional slag processing method. Steel slag having a high viscosity produced by the splashed slag attached to the furnace can be processed by means of a specific slag removal machine. Its shortcoming is that the current rolling cylinder device cannot achieve a cleaning processing to ladle-bottom slag. Because the ladle-bottom slag has a large lumpiness, has not any fluidity, it cannot be directly poured into the current rolling cylinder device, so that a specific slag turning field is needed, onto which the ladle-bottom slag and a portion of high-viscosity slag remained after slag removal are poured, for a conventional cooling and crushing. Therefore, the efficiency is influenced, and dust emission occurs.